Remove unnecessary Document.h includes in .cpp files

Source/core/rendering/RenderButton.cpp

 /**
  * Copyright (C) 2005 Apple Computer, Inc.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Library General Public License for more details.
  *
  * You should have received a copy of the GNU Library General Public License
  * along with this library; see the file COPYING.LIB.  If not, write to
  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  * Boston, MA 02110-1301, USA.
  *
  */
 
 #include "config.h"
 #include "core/rendering/RenderButton.h"
 
-#include "core/dom/Document.h"
-
 namespace WebCore {
 
 using namespace HTMLNames;
 
 RenderButton::RenderButton(Element* element)
     : RenderFlexibleBox(element)
     , m_inner(0)
 {
 }
 
@@ skipping 93 matching lines @@
         // baseline for the empty case manually here.
         if (direction == HorizontalLine)
             return marginTop() + borderTop() + paddingTop() + contentHeight();
 
         return marginRight() + borderRight() + paddingRight() + contentWidth();
     }
     return RenderFlexibleBox::baselinePosition(baseline, firstLine, direction, linePositionMode);
 }
 
 } // namespace WebCore